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Instantaneous wave-free ratio (iFR) can reliably assess the physiological significance of coronary artery disease (CAD). Previous studies have demonstrated its interchangeability with other non-hyperaemic pressure ratios (NHPR), but there is no data exploring whether this association is maintained in patients with severe aortic stenosis (AS).Forty-two patients (67 lesions) with severe AS were recruited and underwent invasive pressure-wire assessment. Data were extracted to calculate iFR, resting Pd/Pa, diastolic pressure ratios (DPR and dPR), and Diastolic Hyperaemia-Free Ratio (DFR). iFR was then compared with other NHPR to determine agreement and accuracy.Mean aortic gradient and dimensionless index were 44.3 ± 11.6 mmHg and 0.23 ± 0.04, respectively. Of the 67 vessels, 57% were LAD, 15% LCx, 13% RCA and 12% other. There was strong positive correlation between iFR and all other NHPR, including Pd/Pa (r = 0.91, p0.001), DPR (r = 0.99, p0.001), dPR (r = 0.97, p0.001) and DFR (r = 0.98, p0.001). While Bald-Altman analysis demonstrated that Pd/Pa and DFR were numerically different from iFR, ROC analyses demonstrated iFR ≤0.89 was accurately identified by all NHPRs; Pd/Pa (AUC = 0.965, 95% CI [0.928-0.994]), DPR (AUC = 1.000, 95% CI [1.000-1.000]), dPR (AUC = 0.974, 95% CI [0.937-1.000]), DFR (AUC = 0.989, 95% CI [0.968-1.000]).In patients with severe AS, all the included NHPR in this analysis accurately predicted iFR0.89. These data should reassure clinicians that use of alternative NHPR to iFR is reasonable when assessing the physiological significance of CAD in patients with severe AS.

Introduction The Perceval Valve has been increasingly used in Surgical Aortic Valve Replacement (SAVR) recently due to ease of implantation. However, we have seen some cases of relatively early haemodynamic failure of the Perceval valve and these patients may then present for valve-in-valve transcatheter aortic valve implantation (ViV-TAVI). Experience of ViV-TAVI in the Perceval valve is limited. Methods We report our experience of VIV-TAVI in four cases of early-failing Perceval valves, two with stenosis and two with regurgitation. We also review the literature with regard to ViV-TAVI for this indication. Results Four patients aged between 66 and 78 years presented with Perceval valve dysfunction an average of 4.6 years following SAVR. All cases underwent Heart Team discussion and a ViV-TAVI procedure was planned thereafter. Strategies to ensure crossing through the centre of the valve and not outside any portion of the frame were found to be essential. Three patients had self-expanding valves implanted and one had a balloon-expandable prosthesis. The average aortic valve area (AVA) improved from 0.8 cm 2 pre-procedure to 1.5 cm2 post-procedure*. The mean gradient (MG) improved from 35.5 mmHg (range 19.7–53 mmHg) pre-procedure to 14.8 mmHg (range 7–30 mmHg) post-procedure. In one patient a MG of 30 mmHg persisted following valve deployment. There were no significant peri-procedural complications. Conclusions ViV-TAVI is a useful option for failed Perceval prostheses and appears safe and effective in this small series. Crossing inside the whole frame of the Perceval valve is essential.

BACKGROUND: Quantitative flow ratio (QFR) may be used to assess the functional significance of coronary lesions. Only limited validation exists for this technology in the setting of severe aortic stenosis. METHODS: A prospective study was performed on patients who were being considered for transcatheter aortic valve implantation. QFR analysis was performed (Medis Medical Imaging System, Leiden, The Netherlands) and compared to invasive measurements of haemodynamic assessment [fractional flow reserve (FFR), instantaneous wave-free ratio (iFR), diastolic pressure ratio during the wave-free period (dPR) and distal arterial pressure/arterial pressure (Pd/Pa)]. RESULTS: A total of 35 patients were included in the study. Mean age was 75.5±6.5 and mean aortic valve gradient was 44.3±11.8 mmHg. There were 57 vessels analysed. The mean FFR was 0.83±0.10 and 22 vessels (39%) had a functionally significant FFR ≤0.80. QFR demonstrated a discriminatory power to predict functionally significant FFR [area under the receiver operating characteristic curve (AUC), 0.92; 95% confidence interval (CI): 0.84 to 1.00], representing a sensitivity of 73%, specificity of 91%, positive predictive value of 84%, negative predictive value of 84% and an accuracy of 84%. QFR also demonstrated a discriminatory power to predict functionally significant iFR ≤0.89 (AUC =0.92; 95% CI: 0.85 to 0.99), dPR ≤0.89 (AUC =0.90; 95% CI: 0.83 to 0.98) and Pd/Pa ≤0.92 (AUC =0.89; 95% CI: 0.80 to 0.97). CONCLUSIONS: QFR demonstrates acceptable diagnostic performance in patients with severe aortic stenosis when both FFR and non-hyperaemic pressure indices are used as reference standards.

Right bundle-branch block (RBBB) is a strong predictor of the development of high-grade AV block (AVB) after TAVI.To assess mortality, length-of-hospital stay, and cost in patients with RBBB undergoing TAVI according to whether or not they had preprocedural permanent pacemaker (PPM) implantation.A total of 121 patients with RBBB who underwent TAVI between 2009-2021 were included. A total of 41 patients (33.9%) received a prophylactic PPM by clinical preference and 45/80 patients (56%) received PPM after TAVI. Baseline characteristics were balanced. Mortality was similar at 5 years, with death in 17 patients (41.4%) in the prophylactic PPM group vs 27 (33.8%) in the no prophylactic PPM group (adjusted hazard ratio [HR], 1.27; 95% confidence interval [CI], 0.69-2.33; P=.44). Median survival for the prophylactic PPM (4.2 years), post TAVI PPM (4.5 years) and no pacemaker (4.7 years) groups was similar. Sixteen deaths (35.6%) occurred in those receiving PPM after TAVI and 11 deaths (31.4%) occurred in those not receiving PPM (HR, 0.95; 95% CI, 0.43-2.09; P=.90). Thirty-day all-cause mortality was similar. Compared with post-TAVI PPM, prophylactic PPM reduced hospital length of stay (4.3 ± 4.5 days vs 2.5 ± 1.6 days, respectively; P=.02). For the highest and lowest complication and comorbidity scores, prophylactic PPM resulted in cost savings of £297.32 (-2.9%) and excess cost of £423.89 (+5.6%), respectively. There were no major pacing-related complications.More than half of patients with RBBB undergoing TAVI require PPM shortly after their valve implant. A prophylactic pacing strategy is safe, reduces length of hospital stay, and is cost effective in the United Kingdom.

We report a single-center experience in utilizing the transcaval-access transcatheter aortic valve implantation (TAVI) as an alternative approach in morbidly obese patients.Morbidly obese patients present frequently for TAVI. Transfemoral arterial access TAVI in these patients is technically challenging due to deep arterial access, resulting in a higher risk of vascular complications. Transcaval access TAVI is increasingly used in patients with prohibitive iliofemoral arterial access.We used the transcaval approach for eight morbidly obese patients who had otherwise technically feasible femoral arterial access. This technique provides an alternative arterial access point that potentially circumvents some of the challenges relating to femoral arterial access.We report eight morbidly obese patients with a mean body mass index of 42.3 ± 6.2 kg/mTranscaval access TAVI is a feasible alternative for morbidly obese patients and may reduce vascular complications. Further data are required to evaluate the safety of this approach.

The clinical predictors and sequelae of leaflet thrombosis (LT) following transcatheter aortic valve replacement (TAVR) is still unclear. Therefore, our aim was to determine the clinical predictors and sequelae at mid-term follow-up of computed tomography (CT)-defined LT following TAVR. We performed a prospective evaluation with a 320-multislice CT following TAVR for the presence of LT, defined as hypo-attenuated leaflet thickening (HALT). Four-dimensional CT image-rendering was performed to determine the presence of reduced leaflet motion (RELM). 172 patients [89 (51.7%) male, mean age 82.8 ± 5.7 years] treated with commercially available TAVR device (Lotus 54%, CoreValve 32% and Sapien 3 14%) were included, with median CT-scan at 6.0 weeks post-TAVR. Prevalence of HALT was 14.0% (24 cases) and RELM was 9.8% (17 cases). On multivariate analysis, patients with HALT were less prescribed oral anticoagulation (OAC) (OR 9.9), received larger TAVR prostheses (OR 5.7) and higher rates of moderate-severe para-valvular regurgitation (PVR) (OR 16.3). There was no difference in clinical outcomes at a median follow-up of 2.3 years. Patients with RELM had significantly higher transvalvular gradients after discharge when compared to those without RELM. Absence of OAC, large TAVR prostheses and moderate-severe PVR were predictors for LT. Transvalvular gradients were higher in patients that developed RELM but not HALT. Further studies are warranted to determine the long-term impact of LT on TAVR durability. Prevalence of different sub-types of CT-defined LT (HALT and RELM) and the clinical predictors of developing LT following TAVR. CT computed tomography, HALT hypo-attenuated leaflet thickening, LT leaflet thrombosis, RELM reduced leaflet motion, TAVR transcatheter aortic valve replacement

The pathophysiology of coronary atherosclerosis is multifaceted. Plaque initiation and progression are governed by a complex interplay between genetic and environmental factors acting through processes such as lipid accumulation, altered haemodynamics and inflammation. There is increasing recognition that biomechanical stresses play an important role in atherogenesis, and integration of these metrics with clinical imaging has potential to significantly improve cardiovascular risk prediction. In this review, we present the calculation of coronary biomechanical stresses from first principles and computational methods, including endothelial shear stress (ESS), plaque structural stress (PSS) and axial plaque stress (APS). We discuss the current experimental and human data linking these stresses to the natural history of coronary artery disease and explore the future potential for refining treatment options and predicting future ischaemic events.

Background Hypo-attenuated leaflet thickening (HALT) may occur following transcatheter aortic valve replacement (TAVR), however, it remains unclear if HALT is a predictor of haemodynamic valve deterioration (HVD). Aim To determine the impact of HALT on the occurrence of HVD. Methods We prospectively evaluated 186 patients for the presence of HALT at a median of 6 weeks following TAVR (Interquartile-range [IQR] 4–12 weeks). HALT depth and area were measured. HVD encompassed any of the following: mean gradient ≥20 ​mmHg with an increase in gradient ≥10 ​mmHg from baseline, Doppler velocity index reduction ≥0.1 or new moderate-to-severe valvular regurgitation. Routine echocardiograms at discharge, one month and annually, were assessed by echo-cardiologists that were blinded to the HALT status. Results LT prevalence was 17.7% (33/186). HVD was present in 8.6% (16/186) at a median follow-up of 2 years (IQR 1–3); two required valve re-intervention and five required anticoagulation. HALT was the only independent predictor of HVD on multivariate analysis (OR 33.3, 95%CI 7.4–125). Patients with HALT were more likely to develop HVD, require repeat valve intervention and have higher trans-valvular gradients at up to 3-year follow-up. Patients with HALT had a median cumulative thickness of 2.9 ​mm (IQR 1.9–4.7) and area of 64.2 ​mm2 (IQR 40.9–91.6). Thresholds for HALT in predicting HVD were a cumulative depth of 2.4 ​mm (Specificity 94.1%, Sensitivity 75.0%, AUC ​= ​0.87) and cumulative area of 28 ​mm2 (Specificity 92.2%, Sensitivity 81.3%, AUC ​= ​0.86). Conclusion HALT is an independent predictor of HVD, which exhibits specific depth and area thresholds to predict HVD. CT following TAVR may determine patients at risk of HVD.

BACKGROUND Selection of appropriate patients for transcatheter aortic valve implantation (TAVI) can be challenging. Many factors can influence post-procedure outcomes. Traditional surgical scoring systems do not discriminate effectively. Medical parameters and functional indices can characterize mortality risk. Mobility is an important predictive functional index but is largely defined using subjective criteria. AIM To describe the relationship between mobility, objectively defined by the requirement for gait aids to ambulate, and all-cause 30-day and long-term mortality in patients undergoing TAVI. METHODS Mobility aid use was assessed in 1444 consecutive patients undergoing TAVI in a single center. Patients were categorized into "unaided," "1-stick," and "higher aid" groups based on the Brighton Mobility Index. Mortality tracking was obtained via the NHS Spine Portal in February 2021. RESULTS Patients were aged 82 (IQR 78-86). 66% of patients walked unaided, 26% walked with 1 stick, and 8% required more assistance (e.g., 2 sticks, a Rollator, a Zimmer frame, or a wheelchair). Overall 30-day mortality for the whole cohort was 3.5%; 1-year mortality was 12.2%. Mobility was a significant predictor of 30-day mortality (p = 0.025). Use of a higher aid was associated with a mortality odds ratio of 2.83 (95% CI: 1.39-5.74). Mobility was also a significant predictor of long-term mortality (p

Aortic stenosis (AS) and coronary artery disease (CAD) frequently coexist, with up to two thirds of patients with AS having significant CAD. Given the challenges when both disease states are present, these patients require a tailored approach diagnostically and therapeutically. In this review the authors address the impact of AS and aortic valve replacement (AVR) on coronary hemodynamic status and discuss the assessment of CAD and the role of revascularization in patients with concomitant AS and CAD. Remodeling in AS increases the susceptibility of myocardial ischemia, which can be compounded by concomitant CAD. AVR can improve coronary hemodynamic status and reduce ischemia. Assessment of the significance of coexisting CAD can be done using noninvasive and invasive metrics. Revascularization in patients undergoing AVR can benefit certain patients in whom CAD is either prognostically or symptomatically important. Identifying this cohort of patients is challenging and as yet incomplete. Patients with dual pathology present a diagnostic and therapeutic challenge; both AS and CAD affect coronary hemodynamic status, they provoke similar symptoms, and their respective treatments can have an impact on both diseases. Decisions regarding coronary revascularization should be based on understanding this complex relationship, using appropriate coronary assessment and consensus within a multidisciplinary team.

Background: Coronary artery disease is common in patients with severe aortic stenosis. Computed tomography-derived fractional flow reserve (CT-FFR) is a clinically used modality for assessing coronary artery disease, however, its use has not been validated in patients with severe aortic stenosis. This study assesses the safety, feasibility, and validity of CT-FFR in patients with severe aortic stenosis. Methods: Prospectively recruited patients underwent standard-protocol invasive FFR and coronary CT angiography (CTA). CTA images were analyzed by central core laboratory (HeartFlow, Inc) for independent evaluation of CT-FFR. CT-FFR data were compared with FFR (ischemia defined as FFR ≤0.80). Results: Forty-two patients (68 vessels) underwent FFR and CTA; 39 patients (92.3%) and 60 vessels (88.2%) had interpretable CTA enabling CT-FFR computation. Mean age was 76.2±6.7 years (71.8% male). No patients incurred complications relating to premedication, CTA, or FFR protocol. Mean FFR and CT-FFR were 0.83±0.10 and 0.77±0.14, respectively. CT calcium score was 1373.3±1392.9 Agatston units. On per vessel analysis, there was positive correlation between FFR and CT-FFR (Pearson correlation coefficient, R =0.64, P P P =0.01 and P P Conclusions: CT-FFR is safe and feasible in patients with severe aortic stenosis. Our data suggests that the diagnostic accuracy of CT-FFR in this cohort potentially enables its use in clinical practice and provides the foundation for future research into the use of CT-FFR for coronary evaluation pre-aortic valve replacement.

Patients with severe aortic stenosis (AS) exhibit systemic endothelial dysfunction, which can be associated with myocardial ischaemia in absence of obstructive coronary disease. Transcatheter aortic valve replacement (TAVR) is used to treat severe AS in patients with high or prohibitive surgical risk. However, it remains unknown whether endothelial function recovers post-TAVR. We therefore sought to assess the early and late changes in flow-mediated dilation (FMD), a measure of endothelial function, following TAVR.Patients undergoing TAVR for severe AS had ultrasound assessment of brachial endothelial-independent and -dependent FMD. Measurements were performed pre-TAVR, at early follow-up (48 h post-TAVR) and late follow-up (4-6 weeks post-TAVR).27 patients (mean age 82.0 ± 7.0; 33.3% female) were recruited; 37.0% had diabetes mellitus and 59.3% had hypertension. Brachial artery FMD increased from 4.2 ± 1.6% (pre-TAVR) to 9.7 ± 3.5% at early follow-up (p0.0001). At late follow-up, improvement compared with early follow-up was sustained (8.7 ± 1.9%, p = 0.27). Resting brachial arterial flow velocities decreased significantly at late follow-up (11.24 ± 5.16 vs. 7.73 ± 2.79 cm/s, p = 0.003). Concordantly, at late follow-up, there was decrease in resting wall shear stress (WSS; 14.8 ± 7.8 vs. 10.6 ± 4.8dyne/cm2, p = 0.01), peak WSS (73.1 ± 34.1 vs. 58.8 ± 27.8dyne/cm2, p = 0.03) and cumulative WSS (3543 ± 1852 vs. 2504 ± 1089dyne·s/cmEndothelial function in patients with AS improves early post-TAVR and this improvement is sustained. This likely occurs as a result of improved arterial haemodynamics, leading to lower localised WSS and release of vasoactive mediators that may also alleviate myocardial ischaemia.

The clinical predictors and sequelae of leaflet thrombosis (LT) following transcatheter aortic valve replacement (TAVR) is still unclear. Therefore, our aim was to determine the clinical predictors and sequelae at mid-term follow-up of computed tomography (CT)-defined LT following TAVR.We performed a prospective evaluation with a 320-multislice CT following TAVR for the presence of LT, defined as hypo-attenuated leaflet thickening (HALT). Four-dimensional CT image-rendering was performed to determine the presence of reduced leaflet motion (RELM). 172 patients [89 (51.7%) male, mean age 82.8 ± 5.7 years] treated with commercially available TAVR device (Lotus 54%, CoreValve 32% and Sapien 3 14%) were included, with median CT-scan at 6.0 weeks post-TAVR. Prevalence of HALT was 14.0% (24 cases) and RELM was 9.8% (17 cases). On multivariate analysis, patients with HALT were less prescribed oral anticoagulation (OAC) (OR 9.9), received larger TAVR prostheses (OR 5.7) and higher rates of moderate-severe para-valvular regurgitation (PVR) (OR 16.3). There was no difference in clinical outcomes at a median follow-up of 2.3 years. Patients with RELM had significantly higher transvalvular gradients after discharge when compared to those without RELM.Absence of OAC, large TAVR prostheses and moderate-severe PVR were predictors for LT. Transvalvular gradients were higher in patients that developed RELM but not HALT. Further studies are warranted to determine the long-term impact of LT on TAVR durability. Prevalence of different sub-types of CT-defined LT (HALT and RELM) and the clinical predictors of developing LT following TAVR. CT computed tomography, HALT hypo-attenuated leaflet thickening, LT leaflet thrombosis, RELM reduced leaflet motion, TAVR transcatheter aortic valve replacement.

BACKGROUND: Quantitative flow ratio (QFR) is an estimate of fractional flow reserve (FFR) and is derived from 3-dimensional quantitative coronary angiography. The DILEMMA score is an angiographic technique developed to predict FFR. Unlike other diastolic indices such as instantaneous wave-free ratio (iFR), diastolic pressure ratio (dPR) and dPR(25–75), neither QFR nor DILEMMA score require pressure wires. This study sought to compare the diagnostic performance of QFR, diastolic indices and DILEMMA score to predict FFR. METHODS: Between January 2010 and December 2013, patients who underwent invasive coronary angiography and FFR assessments were retrospectively studied. iFR and dPR were derived from FFR pressure tracings. QFR was computed using commercial software. RESULTS: Eighty-five lesions (25% FFR significant) were included in this study. Median FFR was 0.88 (0.81–0.92). QFR (r(s)=0.801), iFR (r(s)=0.710), dPR (r(s)=0.716), dPR(25–75) (r(s)=0.715) and DILEMMA score (r(s)=−0.623) significantly correlated with FFR (P

Severe aortic stenosis induces abnormalities in central aortic pressure, with consequent impaired organ and tissue perfusion. Relief of aortic stenosis by transcatheter aortic valve replacement (TAVR) is associated with both a short- and long-term hypertensive response. Counterintuitively, patients who are long-term normotensive post-TAVR have a worsened prognosis compared with patients with hypertension, yet the underlying mechanisms are not understood. We investigated immediate changes in invasively measured left ventricular and central aortic pressure post-TAVR in patients with severe aortic stenosis using aortic reservoir pressure, wave intensity analysis, and indices of aortic function. Fifty-four patients (mean age 83.6±6.2 years, 50.0% female) undergoing TAVR were included. We performed reservoir pressure and wave intensity analysis on invasively acquired pressure waveforms from the ascending aorta and left ventricle immediately pre- and post-TAVR. Following TAVR, there were increases in systolic, diastolic, mean, and pulse aortic pressures (all P P =0.30) whereas excess pressure increased 47% (29.0±10.9 versus 42.6±15.5 mm Hg, P 3 au, P 3 au, P =0.01) and forward expansion wave energies (43.2±27.3 versus 82.8±53.1, ×10 3 au, P

The use of fractional flow reserve (FFR) in guiding revascularisation improves patient outcomes and has been well-established in clinical guidelines. Despite this, the uptake of FFR has been limited, likely attributable to the perceived increase in procedural time and use of hyperaemic agents that can cause patient discomfort. This has led to the development of instantaneous wave-free ratio (iFR), an alternative non-hyperaemic pressure ratio (NHPR). Since its inception, the use of iFR has been supported by an increasing body of evidence and is now guideline recommended. More recently, other commercially available NHPRs including diastolic hyperaemia-free ratio and resting full-cycle ratio have emerged. Studies have demonstrated that these indices, in addition to mean distal coronary artery pressure to mean aortic pressure ratio, are mathematically analogous (with specific nuances) to iFR. Additionally, there is increasing data demonstrating the equivalent diagnostic performance of alternative NHPRs in comparison with iFR and FFR. These NHPRs are now integral within most current pressure wire systems and are commonly available in the catheter laboratory. It is therefore key to understand the fundamental differences and evidence for NHPRs to guide appropriate clinical decision-making.

Coronary artery disease (CAD) is common in patients undergoing transcatheter aortic valve replacement (TAVR), although its prognostic significance is questionable. Significant CAD stratified using SYNTAX score (SS) has been associated with greater mortality, yet it is unknown whether the functional impact of CAD also impacts outcomes in this cohort. DILEMMA score (DS) is a validated angiographic functional scoring tool that correlates with fractional flow reserve and instantaneous wave-free ratio. This study sought to assess the functional impact of CAD on outcomes in patients undergoing TAVR for severe aortic stenosis (AS).229 patients were included in this analysis. Patients underwent angiographic DS and SS and were classified using predefined values. The primary endpoint was one-year all-cause mortality, with secondary endpoints of 30-day major adverse cardiac and cerebrovascular events (MACCE).The mean age was 83.9 ± 0.5 years (55.0% female), with 11.8% all-cause mortality. CAD defined by ≥30% stenosis in any vessel was not associated with adverse outcomes (HR = 1.08, p = 0.84). However, the risk of one-year mortality was greater in patients with either SS 9 (20.8% vs. 9.4%, HR 2.34, p = 0.03) or DS 2 (18.4% vs. 8.5%, HR = 2.28, p = 0.03). Both scoring systems were also associated with 30-day MACCE (both p 0.05). After multivariate adjustment, independent predictors of one-year mortality were DS 2 (HR = 2.29, p = 0.04), left ventricular ejection fraction50% (HR 2.66, p = 0.04) and COPD (HR 2.43, p = 0.04).Our results demonstrate that angiographic functional scoring is independently predictive of both 12-month mortality and 30-day MACCE following TAVR.

Fractional flow reserve (FFR) is routinely used to determine lesion severity prior to percutaneous coronary intervention (PCI). However, there is an increasing recognition that FFR may also be useful following PCI to identify mechanisms leading to restenosis and the need for repeat revascularization. Post-PCI FFR is associated with the presence and severity of stent under-expansion and may help identify peri-stent-related complications. FFR pullback may also unmask other functionally significant lesions within the target vessel that were not appreciable on angiography. Recent studies have confirmed the prognostic utility of performing routine post-PCI FFR and suggest possible interventional targets that would improve stent durability. In this review, we detail the theoretical basis underlying post-PCI FFR, provide practical tips to facilitate measurement, and discuss the growing evidence supporting its use.

The heart is a dynamic organ that beats >2.5 billion times in the average lifetime. Humankind's fascination for its complex yet elegant physiology can be traced as far back as the ancient Egyptians, who first documented the association between abnormalities in the peripheral pulse and the heart. Several thousand years later, in the 17th century, an English physician named William Harvey provided a more comprehensive interpretation of the mechanisms of the systemic circulation. A sound grasp of cardiovascular physiology is pertinent to the understanding of many of the pathophysiological processes in the body and is thus an essential for all aspiring physicians. In this article, we discuss the basic physiological, electrophysiological and haemodynamic concepts of the heart.

A 73-year-old farmer presented with platypnoea-orthodeoxia syndrome (POS). A transoesophageal echocardiogram (TOE) disclosed a patent foramen ovale (PFO) with significant right-to-left shunt on assuming upright posture. An initial attempt at PFO closure through the femoral vein was abandoned due to a completely occluded inferior vena cava. A second attempt through the internal jugular vein was also unsuccessful due to the steep angulation between superior vena cava and septum primum flap. Because of disabling symptoms, an attempt through a hepatic vein (HV) was scheduled and performed under general anaesthesia with TOE guidance. Ultrasound-guided access through an intercostal window to a peripheral HV was performed and the position confirmed with contrast injections. The PFO was easily crossed with a glide wire which was exchanged to a stiffer guide wire. A 25mm closure device was successfully deployed across the PFO. After retrieval of the delivery system, haemostasis of the HV was attained with a contrast-guided Gelfoam (Pfizer, New York, NY, USA) injection. Unfortunately, the patient had to undergo subsequent emergency coiling to an iatrogenically injured hepatic artery branch leading to full recovery and significant clinical improvement. Subsequent echocardiography demonstrated a well-positioned device with no residual shunt. This case illustrates that percutaneous PFO closure through a HV is a feasible procedure and should be considered in anatomy that is otherwise prohibitive for conventional approach. Extra care should be taken with initial vascular access into the HV and final haemostasis of the access site.

An 82-year-old man underwent elective transcatheter aortic valve replacement (TAVR) for severe aortic stenosis. He was a participant in a study involving intracoronary Doppler and pressure assessment using a ComboWire (Volcano, San Diego, California) before and after valve deployment (Australian New

Coronary artery disease remains the leading cause of death in the developed world. Over recent years, research has been focused on the development of diagnostic intravascular imaging techniques that enable assessment of plaque composition and morphology, and allow identification of vulnerable, high-risk lesions. Nevertheless recent studies of coronary atherosclerosis have shown that invasive modalities have a limited accuracy in detecting lesions that will progress and cause events, whilst histology-based studies also highlighted the limitations of invasive imaging in assessing plaque characteristics. To overcome these drawbacks, multimodality imaging has been proposed. Although it is apparent that coronary imaging with two or three imaging modalities is time consuming and is associated with a risk of complications, evidence from small clinical studies demonstrated that it provides incremental information about plaque pathology and biology and underscored the need to develop dual-probe hybrid imaging catheters that would enable complete and comprehensive assessment of plaque morphology. This paper reviews the current clinical evidence that supports the use of multimodality intravascular imaging in the study of atherosclerosis, summarizes the key findings of the first invasive imaging studies that utilize hybrid dual-probe catheters, and discusses the limitations of combined intravascular imaging that restrict its broad application in both the clinical and research arena.

The role of fractional flow reserve to guide revascularization in patients with stable angina is well established. The instantaneous wave-free ratio (iFR) is an emerging adenosine-free resting index that is non-inferior to FFR and has potential to streamline the functional evaluation of coronary artery disease. The feasibility and utility of intracoronary physiology in patients with acute coronary syndrome (ACS) is unclear. This review will discuss the physiological principles and validity of using FFR and iFR in patients presenting with ACS. We will also provide an overview of the available evidence for their role in guiding revascularization in this patient group. The use of intracoronary physiology in culprit lesions of patients presenting with STEMI is not recommended and its accuracy is uncertain in patients with NSTEMI. In contrast, the physiological assessment of non-culprit vessels with FFR and IFR is a reliable measure of lesion-specific ischemia. Recent studies have demonstrated that FFR-guided revascularization of non-culprit lesions improves clinical outcomes although the role of iFR in this patient cohort is unknown. Physiology-guided revascularization of non-culprit ACS lesions improves clinical outcomes. Future studies investigating the complementary role of plaque morphology, biomechanics, and systemic inflammation may provide clinicians with a more comprehensive framework to guide treatment decisions.

Background Fractional flow reserve (FFR) and non-hyperaemic pressure ratios (NHPRs) are well-validated tools that assess the physiological significance of coronary artery disease (CAD). Low coronary lumen to myocardial mass (V/M) ratio on CT is associated with lower FFR/NHPRs and predisposes towards ischaemia in CAD. Whilst CAD and aortic stenosis (AS) frequently co-exist, patients report angina despite obstructive disease. Purpose We therefore sought to study the interrelationship between V/M and invasive pressure indices in patients with severe AS. Methods 35 patients with severe AS were prospectively recruited as part of CAST-FFR study. Patients underwent CT coronary angiography and invasive pressure-wire assessment. All pressure-indices were assessed in the left anterior descending artery (LAD). Data was extracted to calculate FFR, iFR, diastolic pressure ratios (DPR and dPR) and Diastolic Hyperaemia-free Ratio (DFR). Patient-specific V/M were extracted off-site by independent core lab. Results Mean age was 75±7.5 years, median V/M ratio was 20.7 and mean aortic gradient and DI were 44.3±11.6mmHg and 0.23±0.4 respectively. 79% of patients had CADRADs score of Conclusion Patients with severe AS exhibit high rates of abnormal FFR and NHPR values, despite having no obstructive CAD. Their propensity for having abnormal physiological results is, in part, influenced by coronary volume to mass ratio. These results are important for clinicians considering using invasive physiological tools to guide revascularisation decisions in patients with severe AS. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Monash University, Cardiac Society of Australia and New Zealand Correlation between NHPR/FFR and VMInvasive pressure indices and VM

OBJECTIVES: We sought to assess the validity of the DILEMMA score against instantaneous wave-free ratio (iFR) and evaluate its utility in rationalizing the number of patients referred for invasive physiological assessment. BACKGROUND: The DILEMMA score is a validated angiographic scoring tool incorporating minimal lumen diameter, lesion length and subtended myocardial area that has been shown to predict the functional significance of lesions as assessed by fractional flow reserve (FFR). METHODS: Patients in the DEFINE-FLAIR study who had coronary stenosis of intermediate severity were randomized to either FFR or iFR. DILEMMA score was calculated retrospectively on a subset of this cohort by operators blinded to FFR or iFR values. RESULTS: Three hundred and forty-six lesions (181 assessed by FFR; 165 by iFR) from 259 patients (mean age 66.0 years, 79% male) were included. A DILEMMA score ≤ 2 had a negative predictive value of 96.3% and 95.7% for identifying lesions with FFR >0.80 and iFR >0.89, respectively. A DILEMMA score ≥ 9 had a positive predictive value of 88.9% and 100% for identifying lesions with FFR ≤0.80 and iFR ≤0.89, respectively. The receiver operating characteristic area under the curve values for DILEMMA score to predict FFR ≤0.80 and iFR ≤0.89 were 0.83 (95% CI 0.77–0.90) and 0.82 (0.75–0.89) respectively. A DILEMMA score ≤ 2 or ≥9 occurred in 172 of the 346 lesions (49.7%). CONCLUSIONS: Using DILEMMA score in patients with coronary stenosis of intermediate severity may reduce the need for pressure wire use, offering potential cost-savings and minimizing the risks associated with invasive physiological lesion assessment.

Objectives: A reservoir pressure model describing left ventricular-large artery interaction has been proposed as a useful heuristic model providing insight into the propagation of the central blood pressure as well as providing clinical prognostic information. A pressure-only approach to calculation of reservoir pressure waves has been proposed but this assumes that the resultant excess pressure is proportional to the volume flow rate out of the left ventricle; this has not been tested in humans. Approach: We use non-invasively acquired central pressure and flow data obtained in the 2nd Australian National Blood Pressure Study to test this assumption and to investigate the use of flow approximations based on excess pressure or an assumed triangular flow pattern in calculation of forward and backwards waves in the aortic root. Main results: Results from 821 subjects showed close association between the shape of measured flow patterns and calculated excess pressure, with mean coefficient of determination R 2 = 0.931 ± 0.046(SD). For directly measured versus triangular flow approximation R 2 was 0.918 ± 0.057. Comparison of the peak amplitudes of forwards (Pf) and backwards (Pb) going pressure waves resulted in significant correlation between Pfmax and Pbmax using both measured flow and the triangular flow approximation (0.83 and 0.79 respectively) and using excess pressure as a flow approximation (Pfmax 0.86 and Pbmax 0.77). All associations for peak pressures and integrals were high with R-values between 0.70 and 0.95. Significance: Pressure-only reservoir wave analysis appears to conform to the inherent assumptions underpinning the mathematical approach employed: this provides support for use of reservoir analysis as a non-invasive method to describe potentially important features and functions of ventriculo-vascular interaction without the requirement for flow measurement.

Regulation of coronary blood flow is maintained through a delicate balance of ventriculoarterial and neurohumoral mechanisms. The aortic valve is integral to the functions of these systems, and disease states that compromise aortic valve integrity have the potential to seriously disrupt coronary blood flow. Aortic stenosis (AS) is the most common cause of valvular heart disease requiring medical intervention, and the prevalence and associated socio-economic burden of AS are set to increase with population ageing. Valvular stenosis precipitates a cascade of structural, microcirculatory, and neurohumoral changes, which all lead to impairment of coronary flow reserve and myocardial ischaemia even in the absence of notable coronary stenosis. Coronary physiology can potentially be normalized through interventions that relieve severe AS, but normality is often not immediately achievable and probably requires continued adaptation. Finally, the physiological assessment of coronary artery disease in patients with AS represents an ongoing challenge, as the invasive physiological measures used in current cardiology practice are yet to be validated in this population. This Review discusses the key concepts of coronary pathophysiology in patients with AS through presentation of contemporary basic science and data from animal and human studies.

The outcomes of patients suffering from acute myocardial infarction are contingent on the time taken to deliver definitive treatment. Evidence has shown that the extent of myocardial salvage is greatest if patients are reperfused in the first 3 h from the onset of symptoms [1]. For every 30-min delay in coronary reperfusion, the relative 1-year mortality rate increases by 7.5% [2]. This has driven physicians and policy-makers to popularize phrases such as ‘time is myocardium’ and concepts such as ‘door-to-balloon’ time—the latter representing the time to reperfusion with an intracoronary device from the arrival of the patient at hospital (Fig. 2.1). The biggest delays and challenges in reducing the time to reperfusion, however, are in fact mostly seen in the prehospital setting. This consists of the time from the onset of symptoms to first medical contact (FMC) and subsequently the time from FMC to diagnosis and then reperfusion treatment—termed ‘system delay’. Patient delay may be multifactorial and depends on a host of issues including socioeconomic factors and access to healthcare. The rapid patient assessment and field diagnosis of myocardial infarction has become a crucial factor in time to reperfusion as it dictates the decision on the most appropriate form of reperfusion treatment accounting for geographical factors and available facilities. Importantly, the prehospital role in the management of acute myocardial infarction also involves the initiation of therapy, the upstream of the hospital-delivered treatment. This commonly involves the administration of antiplatelet and anticoagulant therapy in metropolitan areas, while in remote areas where patients cannot be transferred to hospital facilities in a reasonable time, there are policies in place for administration of field thrombolytic agents. Other aspects of the management may involve intravenous access or, indeed in the cases of cardiac arrest, cardiopulmonary resuscitation. In this chapter we will discuss the management of patients presenting with acute myocardial infarction, in the crucial period ahead of their arrival at the heart attack centre.

Computed tomography (CT)–defined hypoattenuated leaflet thickening (HALT) following transcatheter aortic valve replacement (TAVR) has recently been described. We report the clinical predictors of HALT in this large single-center registry. Consecutive patients that were evaluated with CT following